OK, you probably should have mentioned all this at the beginning but I also appreciate that you probably didn't think it was relevant.
The tech has obviously done something wrong. You are absolutely right, if the jumpering was always incorrect, you would have had a problem before this point.
Now that you have told me all this, I think that we ought to work on the assumption that there is still stuff thats wrongly connected. There may not be of course but as USB connections are extremely important to get right & can damage your board if wrong, then I think this would be the safest option.
Firstly, DO NOT connect any USB devices to your system at the moment, or firewire ones either.
I do really need you to look inside the case though.
I'm gonna start by asking you to just familiarize yourself with the layout of the motherboard before we actually do anything else.
This is a slightly reworking of my previous instructions :
1) Switch Computer off & unplug the power cord
2) open up the case.
3) I want you to locate & make a note of each of the following things on the motherboard. (Please don't touch anything apart from the drive or power cabling if you need to move it out the way. If so, do not disconnect any cables, just gently move it enough to see the motherboard more clearly)
Bottom right corner of board - immediately to the right of the top PCI slot, look for sets of metal pins, each set should look something like this :
o o o o
o o o o o
There should be 2 sets, one labelled JUSB3 and one called JUSB4. They may or may not have cables attached to them (in which case of course, the actual pins will be invisible but the labelling will still be there)
I need to know if they have cables connected to them or not.
If they do have cables, I need to know whether its a single thick cable with a plastic plug at the end or whether there are individual wires - each with its own tiny plastic plug on the end. (each wire will be either red,white,green or black)
Directly below JUSB3 & JUSB4, you should see 2 lots of 3 pin headers. Two of the pins should be covered by a plastic cap.
They should look something like this with these names next to them :
[ o o ] o [ o o ] o
where [oo] is 2 pins covered by cap, and 'o' is bare.
Let me know if both have caps to the left or the right
ie as above or o [ o o ]
Next, look in top left corner of board, to the left of the cpu socket. There should be another of these sets of pins like the last ones, called JUSBV1
This one is vertical instead of horizontal ie.
I need to know if the cap covering it is over the top 2 pins or the bottom 2 pins.
Last thing to check, is bottom left corner/edge of board. There is 2 sets of pins which will look identical to the first 2 sets (ie JUSB4 & JUSB4) but these will be called J1394A1 and J1394B1.
There may be another a bit further along called J1394C1 as well.
I need to know if you can find all 3 & if any have cables connected to them.